Telephone transmitter



Feb. 26, 1924.- 1,485,196

R. L. MURRAY TELEPHONE TRANSMITTER Filed Auz. 24 1921 I Inventor @wgmwAmit mean ries.

ROBERT LAMBERT MURRAY, OF BUSHEY HEATH, ENGLAND, ASSIGNOR TO TELEPHONEMANUFACTURING COMPANY LIMITED, 01 LONDON, ENGLAND.

TELEPHONE TRANSMITTER.

Application flled- August 24, 1921'. Serial No. 494,770.

To all whom it may concern:

Be it known that I, Ronnn'r LAMBERT MURRAY, .a subject of the King'ofEngland, residing in Bushey Heath, Hertfordshire, England, have inventedcertain new and useful Improvements in Telephone Transmitters, of whichthe following is a specification.

This invention relates to telephone transmitters of that type of whichthe diaphragm or a pad thereon is intended to be held in contact with asurface of portion of the users erson, hereinafter referred to in agenera sense as the throat -in contradistinction to the type intended tobe held near the mouth to receive sound transmitted through the air. Theterm pad is intended to denote any projection carried upon the diaphragmitself so as to be interposed between the diaphragm and the surfaceagainst which it is to be pressed so that vibrations are transmittedmechanically through the said projection. v

The object of the present invention is partly to prevent undue pressurebeing exerted between the diaphragm or pad and the users throat andpartly to provide a construction by which the transmitter shall be lessliable to displacement from a convenient position than has heretoforebeen the case.

The present invention therefore provides a telephone transmitter of thetype described provided with one or more members carried by thediaphragm-support and extending therefrom to bear upon the sun face ofthe users person around or closely adjacent to the surface upon whichthe diaphragm or a pad thereon presses. v

Conveniently, according to this invention, a telephone transmitter ofthe'type described is provided with a rigid or other shield carriedby-the diaphragm support, apertured to permit the diaphragm or a padthereon to project through the aperture and shaped or dimensioned tobear upon the users throat surrounding or closely adjacent to that partthereof against which the pad is pressed.

Preferably, according to this invention, a telephone transmitter of thetype described is provided with a shield of elongated form (for exampleof elliptical form) centrally apertured to clear the diaphragm and socarried by the diaphragm-support as to permit the diaphragm to projectbeyond the (not securing rin shield and that the longer dimension of theshield extends in the direction of the length of the users neck when inuse.

The accompanying drawings illustrate, by way of example only, twoembodiments ofthe present invention which give good results,

Figure 1 being a pers ective view ofone form of telephone havlng athroat-transmitter embodying the present invention,

Figure 2 a sectional view taken vertically through the centre of Figure1, and

Figure 3 a side view of a telephone handset embodying the invention,having part of the transmitter broken away to reveal its construction.

Referring first to Figure 2, the transmitter 1 is built together with areceiver 2, upon a foundation ring 3 common to them both. The receivermagnet 4 is encircled by the ring and is mounted upon a base-plate 5which serves to close one otherwise open side of the ring, and the otheropen side is closed by the receiver diaphragm 6 which is covered by adished flanged cap 7, whereof the flange 8 surrounds the ring and issocured to the latter by screws 9. The concavity of the cap is towardsthe diaphragm 6 and a duct 10 leads from the chamber 11 thus formedbetween the diaphragm and the cap through the tubes 12 to the ear piecesshown).

On the exposed side of the base-plate, that is to say the side oppositeto that which carries the receiver magnet, the transmitter is mounted.The transmitter is provided with a diaphragm 13 to which is secured acup 14 in which carbon pellets are received and retained and with acontact plate 15 for the carbon pellets, which plate is secured to thebase-plate 5 by a screw. The diaphragm is held in position by a flanged16 whereof the flange 17 engages the dlaphragm 13 and the body issecured to the foundation ring 3 in any convenient manner. The .saidsecuring ring carries an elliptical larynx shield 18 of ebonite havin a.circular central aperture 19 to allow t e transmitter diaphragm toprotrude slightly therethrough. The said securing ring is provided withtwo diametrically opposite gaps 21' which receive and engagelateralprojections 22 upon the base-plate, which pro'ections areintended to receive the attaching straps, indicated in chain lines-at 23whereby the whole .de-.

vice is held in position upon the, users throat. The longer axis of theshield hes transversely across the line'of the attaching" straps, thatis in the plane of the face of the section shown in Figure 2.

{-When in use the larynx shield serves to' prevent the pressure oftheattaching'str'aps from being entirely transmitted through the"diaphragm tothe' larynx and divertspart of this pressure to thesurrounding muscles thereby relieving'the pressure on the laryi 1x andin some measure predetermming. its

magnitude. a

The shield, moreover, enables the dia'- phragm to be kept properlypresented to the throat with less pressure than-was hereto-- forerequired since without the shield the weight of the device constantlytended to make it tilt outwardly about its lower edge with the resultthat the lower portion of the diaphragm alone remained in contact withthe throat, unless an inconveniently large pressure was maintained bythe attaching straps; the downwardly projecting portion of the shieldafi'ords a-betterleverage -for the attaching straps enabling-thediaphragm to be held againstthe throat with less tension in the straps.It is also found that by this means the transmitter is less liable todisplacement from its correctlocation upon the throat,. which locationappears to be a slight depression, or at least a part occupied withrelatively softer tissues, lying between two muscles, tendons or otherrelatively harder structure of the neck-of the user. The shield may alsoserve to aid in transmitting from the throat to the microphone.

In Figure 3 is shown a handsetof the usual type in which a rigid tube 24supports a receiver 25 secured bv a screw 26 at one end and atransmitter 27 at the other end and has a hand-grip 28 provided aboutits middle. The transmitter, however, is of the kind hereinbeforedescribed as for application to the outside of a users throat. Itcomprises a diaphragm 29 carrying the pellet-cup 30, and a dishedplate-31carry-v ing the pellet contact 32, the plate and the diaphragmbeing held together at their edges in any suitable manner.

These transmitter parts are held in position against the forwardextremity of a cup-shaped casing 33 by a larynx shield 34 of vulcaniteor similar substance of-which an inwardly directed flange 35 engages acooperating outwardly directed edge 36- of resales tralaperturethrough-w-hich the diaphragm I 29'slightly protrudes, theaperture being of such diameter that it is clear, of the protrudingportion of the diaphragm.

If desired, the receiver of this hand set ma be permitted acertain-amount of pivota movement about its'securing screw 26 So that itcan be properly seated against the users ear notwithstanding the angleat which the supporting tube may. have to be held inorder to bring thediaphragm into full contact with the usersthroat.

This construction obviously is particularly suitable for use incircumstances in which a throat-transmitter isdesirable, but.

in which it is not desired to have the mstrument secured about oneparticular users head.

It will be" appreciated that the aforesaid shields are not the onlyforms of shield which will fall within the scope of this invention. Forexample, oppositely. projecting lateral arms of resilient material maybe employed and thesemay be two in number, one on either side, on more,and their free ends may be provided with pads or not,as desired. T WhatI claim as my invention and desire to secure by Letters Patent is 1. Ina telephone transmittenthe combination of a support, a microphonecarried thereby, vibration-transmitting means oper-' atively connectedwith the mlcrophone for directly receiving sound-vibrations from a part0 the. human body and for transmitting the same to' the microphone, andpressure-distributing means carried by the su port and 'spaced radiallyaway from t e margin. {of said 'vibration-transmitting means, whichlatter means extends axially in front of the pressure-distributing meanswhereof the front face is situated so farrearwardly of the front face ofsaidvibra-' tion-transmitting means as to constitute apressure-distributing support for the transmitter when thefront face ofthe vibrationtransmitting means bears against a part of the human body,substantially as described.

2. In a telephone transmitter, the combinationof a support, a diaphragmarranged to receive directly sound-vibrations from a part of the humanbody, a micro hone op eratively connected with said diaphragm andmounted between the same and said support, and a shield that constitutesthe sole means for holding said diaphragm and said-micro hone inposition on thesupport which shie d isearried by the support and has anaperture through which said diamemes phragm extends axially, withmarginal clearance, beyond the front face of the shield, which frontface is situated so far rearwardly of the front face of said diaphragmas to constitute a pressure-distributing support for the transmitterwhen the front face of the diaphragm bears against a part of the humanbody, substantially as described.

3. In a telephone transmitter, the combination of a support, a diaphragmarranged to receive directly sound-vibrations from a part of the humanbody and having an outwardly-directed flange, a microphone 0per-.

atively connected with said diaphragm and mounted between the same andsaid support, and a centrally apertured shield of elliptical formcarried by said support and engaging said flange and thereby holdingsaid diaphragm and said microphone in position on said support, whichshield has its front face situated so far rearWardly of the front faceof said diaphragm as to constitute a pressure-distributing support whenthe front face of the diaphragm bears against a part of the human body,substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

ROBERT LAMBERT MURRAY.

Witnesses:

L. E. GREENACRE, T. J. OSMAN.

